The hypothalamus is a small central region of the brain that regulates body temperature by responding to both internal and external <em>stimuli</em> and also produces the antidiuretic hormone (ADH) in order to trigger the reabsorption of water in the kidneys. The <em>optic</em> <em>chiasma</em> is a special sensory structure located along the visual pathway, directly in front of the hypothalamus, which is crucial to vision. The <em>corpora quadrigemina</em>, also known as quadruple bodies, are reflex centers located in the <em>mesencephalon</em> (midbrain) that regulate the position of the head and eyes in response to somatic <em>stimuli</em>. The <em>cerebellum</em> is a part of the brain located behind the top part of the brain stem which is involved in motor movement regulation and balance control. The thalamus (<em>massa intermedia</em>) is a paired gray matter structure found near the center of the brain that plays vital roles associated with sensory and motor functions of the brain. The <em>medulla oblangata</em> (medulla) is a structure located at the base of the brain involved in the regulation of sensory, motor, and mental functions (e.g., breathing, pain modulation, etc). The<em> corpus callosum</em> (the callosal commissure) is a bundle of nerve fibers that connects the two hemispheres of the brain. The <em>fornix</em> (agenesis of the<em> corpus callosum</em>) is a large interhemispheric commissure that connects neurons in the right and left hemispheres. The cerebral aqueduct (aqueduct of Sylvius) is a narrow channel that connects the third and fourth ventricles, thus allowing the cerebrospinal fluid to flow between the ventricles. Finally, the midbrain o 'mesencephalon' is a small region located in between the forebrain and hindbrain, which is involved in auditory and visual processing, eye movement and coordination.
